Circular electric lamp



Jan. 11, 1944. I w. HARRISON 2,339,166

CIRCULAR ELECTRIC LAMP Filed Oct. 18, 1941 2 Sheets-Sheet l lnvenror:

Ward Harrison,

His Aftorneg.

Jan. 11, 1944. w HARRSON 2,339,166

CIRCULAR ELECTRIC LAMP Filed Oct. 18, 1941 2 Sheets-Sheet 2 /2 u 4/ A 4 /4 J /4 I? /i M U 1, I5 1" v J W [lb -m s lnvenbov: Ward Harrison, by W Patented Jan. 11, 1944 CIRCULAR ELECTRIC LAMP ward Harrison, Shaker Heights, Ohio, assignor to General Electric Company, a corporation of New York Application October 18, 1941, Serial No. 415,594

8 Claims.

This invention relates to lamps of a type comprising long envelopes formed in a bent and more or less nearly closed configuration-a tubular vitreous envelope bent to a circular outline being a representative and very desirable form. For convenience. the general yp of p here volved may be generically referred to as "circular, though it is to be understood that the invention naturally includes lamps whose tubular envelopes are bent to polygonal, oval, or other closed configurations. While the means-.01 translation employed in such a circular lamp for converting electrical energy into useful radiation may be of any kind desired, electrical discharge means are particularly suitable, and especially fluorescent tubes of the usual positive column type. For domestic lighting, a circular fluorescent lamp is very generally more desirable than the long, straight tubes now in common use: e. g., its relative compactness adapts it for installation under the shades of ordinary table lamps and floor lamps, where even low wattage straight tubular lamps would be impracticable. The advantage will readily be appreciated when it is considered that a 30watt fluorescent tube 36 inches long makes a circular lamp such as here illustrated having an overall diameter of only about 12 /2 inches.

Instead of attempting to fabricate an endless tube forming a closed figure or circle, it is preferred to construct the lamp with a tubular envelope having closed ends and curved or bent in a suitable closed configuration, so that these ends lie adjacent and more or less nearly opposite one another. This allows the current connections for the translation means in the tube to be brought out to its exterior at the ends of the tube, and preferably through its end walls. It also allows of constructing and sealing in the tube ends very much as in the manufactur of ordinary straight fluorescent tubes, using-the same cathode mounts as for straight tubes. Indeed, it is even possible to virtually complete the manufacture of th fluorescent lamp as a straight tube. only heating and bending it to the desired final configuration just before exhaust, charging with working substance and starting gas, and sealing oil, etc. for'this purpose are described in U. S. Patents No. 1,534,685, April 21, 1925, Claude and de Beaufort, and No. 2,080,899, May 18, 1937, Pirani and Fehse. Prior to exhaust oi the fluorescent tube, air may be blown into it during bending through an exhaust tubulature forming part of one of its cathode mounts; and, if desired, it may be pro- Methods of bending that may be used vided with such tubulatures at both ends to a1- i'ord hand holds for the bending operation.

Instead of separately basing the envelope ends with bases such as commonly used on straight fluorescent tubes, I provide a common base structure for the juxtaposed envelope ends, equipped with contact terminals for connection to their current connections or leads. These contact terminals may be arranged for access sidewise of the base and of the circular lamp, preferably from the inner side of the lamp tube circle. The common base structure may substantially close the gap between the envelope ends and enclose the current leads of the latter where they come out of the envelope and are connected to the contact terminals, and may interconnect or even surround the envelope ends themselves. Thus the base may completely close th figure oi. the lamp.

Various other features and advantages of the invention will appear from the following description of species or forms of embodiment, and from the drawings.

In the drawings, Fig. 1 is a tilted or perspective view of a circular lamp conveniently embodying the invention; Fig. 2 is a fragmentary tilted view of the lamp base and the associated ends of thelamp envelope, an end of the base and a portion of the envelope being shown in vertical midsection; and Fig. 3 is an exploded tilted view of the parts of the base and the associated lamp tube ends.

Fig. 4 is a fragmentary side view illustrating a base of somewhat different construction; and Fig. 5 is a corresponding exploded view, generally similar to Fig. 3.

Fig. 6 is a tilted or perspective view of a circular lamp with a diflerent form of base embodying the invention; and Fig. '7 is a fragmentary lon itudinal sectional view of the base shown in Fig. 6 and the associated lamp tub ends.

In Figs. 1 and 2, there is shown a positive column fluorescent lamp which may be of the general type disclosed in Patent No. 2,259,040- George E. Inman, and which comprises a glass tube envelope I0 bent to a circular outline and having closed ends I I, ll spaced apart a short distance, though directed toward one another. The approximation of the tube ends II, II to true axial alignmentwill, of course, depend on the technical perfection reached in forming the envelope III in an annular form, as well as on how nearly the circular extent of the envelope approaches 360. As shown in Fig. 2, the tube ends H, II comprise standard cathode mounts I2, I2, of glass stem and flare type, sealed in as usual, and these ends are accordingly somewhat reduced in size at I3, I3. The current connections or leads I4, I4 for the cathodes I5, I of the mounts I2, I2 extend to the exterior of the envelope III at its ends II, II through the stems of the mounts I2, I2, which form the end walls of the envelope. An internal coating of phosphor on the tube walls is indicated at IT, and a supply of mercury is indicated by a droplet I8. In practice, the envelope I!) will also contain a low pressure atmosphere of starting gas, such as argon at a pressure of several millimeters of mercury.

The lamp base structure 20 common to the adjacent envelope ends I I, H is shown in Figs. 1, 2, and 3 as provided with a plurality of contact terminals 2| for connection to the current leads I4. In the present instance, these contacts 2I are accessible sidewise of the base 20 and of the circular lamp envelope I 0, as indicated by the position of a connector 22 opposite the pins in Fig. l, and consist of pins projecting inward from the inner side of the base. The base 20 is shown with an outstanding connector seat 23 around the contact pins 2I. The base 20 may be hollow to engage around the adjacent lamp ends II, I I, and is here shown as a two-part body structure interposed between them and recessed at its own ends to take them. If desired, the reduced tube end portions I3, I3 mav be fixed in the ends of the base 20 by means of basing cement 24, Fig. 2. In the present instance, the tube ends II, I I are so reduced at I3, I3 (Figs. 2 and 3) that the external size or diameter of the base 20 can be uniform with the unreduced main portion of the lamp envelope ID.

The base 20 is divided lengthwise of the lamp I0, preferably in a plane or surface extending (in a general way) circumferentially of the lamp annulus, and its halves-25, 26 are detachably secured or clamped together around the lamp ends II, II by means of a screw bolt 21 with a nut 28. In other words, the base 20 comprises an inner part or block 25 engaging the inner sides of the adjacent envelope ends II, II and having the connector seat 23 at its own inner side, as well as the contact terminals 2I that project from said seat, and an outer part 26 that engages and embraces the outer sides of the envelope ends I I, II, serves as a cover, and is detachably secured to the inner part. The parts 25, 26 may be of any suitable materials, such as molded plastic, for example. I

As best shown in Fig. 3, each of the contact pins 2| has an eccentric elongated head 3| that is accommodated and antiturningly engaged in a recessed seat 32 in the part 25, and may be grooved to receive the end of the correspondin lead I4, which may be soldered to said head 3|. The heads 3| may be held in their seats 32 (and the leads II pressed into contact with them, if not soldered) by the bottoms of corresponding recesses 33 in the part 26. The contact terminals 2I may be polarized in any suitable way to assure correct connection of the connector 22 to them.

Figs. 4 and 5 show a variant form of construction which is in some respects even simpler and more adaptable than that illustrated in Figs. 1 3. As here shown, the base structure 20a is completely hollow from end to end, and of internal size to accommodate the unreduced portions of the tube ends II, II. Accordingly, the base 20a is substantially larger externally than the unreduced main portion of the envelope III. This permits a wide range of variation as regards the distance apart of the tube ends II, I I-so long as there is room between them for the screw bolt 21a that secures or clamps the base halves 25a, 26a together on the tube ends. As in Figs. 1-3, the base parts 25a, 26a may be of molded plastic. As shown in Fig. 5, the contact terminal 'pins 2Ia are fixed in the inner block 25a and extend through this block to its interior, where they have flat heads 3la to which the current leads Ma may be soldered. Accordingly, the part 25a is in effect a housing and terminal block to carry the contact terminals and house their connections, while the part 26a is a cover over the space between the tube ends II, I I.

Fig. 5 illustrates the lateral accessibility of the contacts 2| a from the inner side of the base 20a and of the lamp annulus I0, showing a socketed connector 22 in position to take the contact pins 2Ia.

In Figs. 4 and 5, various parts and features are marked with the same reference numerals as are applied to corresponding parts and features in Figs. 1-3, in order to dispense with repetitive descriptiona distinctive letter being added in Figs. 4 and 5 wherever such distinction appears desirable.

The base construction illustrated in Figs. 6 and 7 differs from those already described in providing for the inclusion of accessories in the base 20b, as well as in regard to the part composing the base and their relation to one another. Like the base 200:. in Figs. 4 and 5, the base 20b in Figs. 6 and Us hollow from end to end, and is divided into coasting parts 25b, 25b. One of these parts, preferably the inner one, 25b, resembles the parts 25, 25a of Figs. 1-5 in being of substantial depth or thickness radially of the lamp tube circle I0, and carries contact terminal pins 2 lb, 2Ib at its own inner side; but it is made hollow to serve as a housing for lamp accessories--here shown as a starting switch 35 (of glow discharge type such as that shown in application Serial No. 400,645--L. R. Peters, filed July 1, 1941), and a condenser 36 intended to prevent radio interference. In the present instance, this part 2512 consists of a molded block of transparent or translucent plastic with an inner recess 31 open into the space between the tube ends II, II, for accommodating the accessories. The use of light-transmitting material in the exposed bottom wall of the recess 31 allows the glow of the switch 35 to be observed; but of course opaque material may be used for the whole part 25b if such observation is not considered worth while. The other part 261) is a cover of sheet metal or other suitable sheet material, and is also hollowed or embossed outward from the center of curvature of the lamp tube I0. Instead of the parts 25b, 26b abutting edgewise at either side of the envelope ends II, II one part 26b embraces the other part 25a at its opposite edges, besides embracing the envelope ends II, II and engaging them at their outer sides as in Figs. -5. Preferably, the margins of the cover part 26b that overlap the edges of the part 25b are secured thereto, as by fasteners 38, 38 such as bolts taking through the ends of the part 25b and of the cover 26!). As here shown, the cover 26b is provided with a flexible insulative liner 39, of fiber or asbestos for example, that surrounds or envelops the parts between the tube ends II, II, and even overlaps the latter.

As shown in Figs. 6 and 7, the ends of the part 25b that engage against the inner sides or the circular envelope ends H, H are hollowed about axes approximately coincident with the axes of the tubular envelope ends II, II, so as to seat properly on the envelope ends; but these hollowed seating surfaces of this part 25b diverge inward from the tube ends. Similarly, the sheet metal of the cover 26b is embossed outward between its end edges that engage and fit against the outer sides of the tube ends II, II in such a way as to diverge outward from the tube ends. This enlargement inward of the hollow of the base 20b with respect to its end openings that accommodate or engage around the tube ends H, II takes care 01' a considerable range 01' variation in the angular relation of these adjacent tube ends in diflerent lamps; while the length oi the base 201) axially of the tube ends takes care 01' considerable variation of the distance apart 01 these ends. As shown in Fig. 7, the holes in the part 25b for the fasteners 38, 38 are elongated crosswise f the tube ends II, II to allow adjustment of the parts 25, 25 relative to one another, to take care of variations of size or of relative direction of the tube ends.

As shown in Figs. 6 and '7, two of the current connections or leads l4, '4 of the cathodes in the tube ends I I, II are connected to the contact terminals 2lb, 2lb. There contact terminals 2|b, 2|b are hollow posts or pins molded into the wall of plastic at the bottom of the recess 31, and thus extending into the interior of the base 20b, and the leads I4, I4 are brought down through them and soldered fast in them, thus holding the part 25b to the tube ends II, II (as shown in Fig. 7) before the cover 26b is put on. The contact terminals Mb, 2"; may be connected acro an A. C. power line P through the usual control switch 8 and choke coil C, which may also serve as a starting inductance. The other two current connections or leads I4, l4 are shown as connected together through the starting glow-switch 35, in parallel with the condenser 36, these parts 3,

36 being conveniently placed in the hollow part 25b and connected as described after the contact terminals Mb, 2": have been connected to the other leads l4, l4. For thi purpose, a connector device or structure 40 is shown in the space between the tube ends H, H at the side thereof adjacent the cover part 28?), consisting of an insulating disc with hollow connector posts 4i, 4| upstanding therefrom at its outer side and provided with peripherally grooved heads 42, 42, which are readily accessible when the cover 2612 is removed. After the parts 35, 38 have been put in place, the connector 40 may b placed over them with their leads extending up through the posts 4|, 4|, and then the proper leads l4, l4 may be wrapped around the heads 42, 42 and the latter soldered to all the leads. It then only remains to place the cover 26b with its insulative liner 39 around thetube ends and the parts between them, and secure the corners 01 its overlapping margins to the edges of the part 25b by the fastener bolts 38, 38.

In Figs. 6 and 7, various parts and features are marked with the same reference numerals as are applied to corresponding ones in Figs, 1-5, in order to dispense with repetitive descriptiona distinctive letter being added where such'distinction appears desirable. However, I do not specifically claim the base construction illus trated in Figs. 6 and 7, since this in its distinctive aspects forms the subject-matter of an appliestion Serial No. 415,597 of Walter J. Geiger of even date, and assigned to the assignee 01' this application.

What I claim as new and desire to secure by Letters Patent of the United States is:

1. An electric lamp comprising a tubular vitreous envelope having electric energy translation means therein for converting electric energy into radiation. and iormed to a bent substantially closed configuration, with its ends adjacent and directed toward one another, and having current connections for said translation means extending out at its ends into the space between them; and a common base body for the tube ends completely enclosing the space between said ends and enclosing their said current connections, thus com-' pleting the closed figure of the lamp, with contact terminals for said current connections carried by said body, said base body being split lengthwise for purposes of assembly.

2. An electric lamp comprising a tubular vitreous envelope having electric energy translation means therein for converting electric energy into radiation, and formed to a bent substantially closed configuration, with its ends adjacent and directed toward one another, and having current connections for said translation means extending to its exterior atits ends; and a common base for said tube ends comprising a body longer than the gap between the tube ends but hollow to accommodate them in its own ends, thus completing the closed figure of the lamp, with contact terminals for said current connections carried by said body and accessible, for connection, sidewise of said body.

3. An electric lamp comprising a tubular vitreous envelope having electric energy translation means therein, for convertingelectric energy into radiation and formed to a bent substantially closed configuration, with its ends adjacent and directed toward one another, and having current connections for said translation means extending to its exterior at its ends, a cover around the opposed envelope ends and the space between them, and a part provided with contact terminals, for connection to said current connections, held to said envelope by said cover and coacting therewith to enclose the space between the envelope ends.

4. An electric lamp comprising a. tubular vitreous envelope having electric energy translation means therein, for converting electric energy into radiation and formed to a bent substantially closed configuration, with its ends adjacent and directed toward one another, and having current connections for said translation means extending to its exterior at its ends, an inner part lying at the inner sides of the opposed envelope ends and having contact terminals at its own inner side for connection to their said current connections, and an outer part lying at the outer sides of the adiacent envelope ends and secured to said inner part.

5. An electric lamp comprising a tubular vitreous envelope having electric energy translation means therein, for converting electric energy into radiation, and formed to a bent substantially closed configuratio with its ends adjacent and directed toward one another, and having current connections for said translation means extending to its exterior at its ends, an inner block lying at the inner sides ofv the opposed envelope ends and provided with connections, and an outer part engaging the terminals for connection to their said t outersides of the adjacent envelope ends, and detachably secured to said inner block.

6. A base for an electric lamp of the type comprising a tubular vitreous envelope having electric energy translation means therein, for converting electric energy into radiation, and formed to a bent substantially closed configuration, with its ends adjacent and directed toward one another, and having current connections for said translation means extending to its exterior at its ends; said base comprising a body longer than the gap between the opposed lamp tube ends, but hollow to accommodate them in its own ends, and contact terminals mounted on said body, for connection to said current connections, and accessible, for connection, sidewise of said body.

7. A base for an electric lamp of the type comprising a tubular vitreous envelope having electric energy translation means therein, for converting electric energy into radiation, and formed to a bent substantially closed configuration, with its ends adjacent and directed toward one another, and having current connections for said translation means extending to its exterior at its ends; said base comprising a body longer than the gap between the opposed lamp tube ends and hollow substantially from end to end, so as to accommodate the ends of lamp tubes with widely varying gaps between their ends, and divided lengthwise, means for detachably securing said parts together around the lamp tube ends, and contact terminals on said body for connection to said current connections of the tube ends.

8. A base for an electric lamp oi. the type comprising a tubular vitreous envelope having electric energy translation means therein, for converting electric energy into radiation, and formed to a bent substantially closed configuration, with its ends adjacent'and directed toward one another, and having current connections for said translation means extending to its exterior at its ends; said base comprising a body longer than the gap between the opposed lamp tube ends, and hollow substantially from end to end, so as to accommodate the ends of lamp tubes with widely varying gaps between their ends, and comprising a cover part to extend around the outer sides of the opposed lamp tube ends and the space between them, an inner part to lie at the inner sides of said tube ends provided with contact terminals at its own inner side for connection to their current connections, and means for securing said parts together around the tube ends.

WARD HARRISON. 

